Telephone system



Jan. 24, 1928.

1,657,117 A. FLAD TELEPHONE SYSTEM File czrApiril 5.1 1926 Vthe. Figure 5.

-t'ected by contactsof relays (not shown) which are connected up in some known manner at the commencement oit the conversation. The Figure a shows another arrange ment, whereby the weakening of the speech currents by the damping devices can be pre y vented. The direct current circuit for generating the induced impulses is' bridged across the outgoing end oi" the trunk line over a special repeater le 3. :W'hen the relay Al. operates, its contact im l closes a direct current circuit over the lett hand winding oi the repeater Ue 3. An induced impulse is thereby generated in the right hand winding ot the, repeater Ue 3 and reaches the left handwinding of a speaking current repeater, the right hand` winding of which is connected to the trunk line taken into use. During the impulse transmission, the same operations taire place as those described with reference to the Figure l. It is not necessary to disconnect the damping `devices IV, Dr and C, because they are only inductively coupled to the speaking leads and can therefore cause no appreciable weakening ot the speech currents.

, Vhen the current impulses are transmitted over longlines, the transmitted in duced current is so weak that the operation of the impulse receiving relay to connect up its holding winding over its own front contact is delayed.` The closing oi this direct current circuit over the holding winding II induces an impulse in the energizing Winding I, `the direction `of this induced impulse being opposite to that of the induced impulse that energized the relay.

The magnetizing `strength et the impulse n n n' I receiving lrelay `1s thereiore proportional to the` diil'ercnce between the `strength `of theV two induced currents. It the induced impulse that energizes the relay be weakened `by the length of the trunk line, it may happen as a result that the relay does not become sufliciently magnetized to` keep .its armature attracted. This detect can easily be removed by means ,of the circuit shown in The impulse receiving relay J, Fig. 1, has its `winding I energized by the induced impulse atthe commencement of an impulse. The relay closes its contact 3y', thereby establishing the following holding circuit for the Winding II: earth, Contact 3y', `winding II of relay J, Contact laf. windi ing et ,the relay H, battery? earth. Tinten rent flowing over this circuit is comparatively strong, so that even though the energizing current iinpulse'be very weak, the armature l will be held in a reliable manina'. The follow-up contacts/i is opened shortly atter the' auxiliary relay Il" `has been operated, thus the resistance W l, which hitherto has been short circuitcd, is placed in the locking circuit of the relay J. The strength of the current in the holding circuit is thereby reduced in order to demagnetize the impulse receiving relay .I in a reliable manner when the winding I oi relay l is energized by the induced impulse arriving at the end of the current impulse.

What is claimed is:

l. In combination, an iuipuiee transuit ting' relay having a` first and a second winding, means i'or producing a current tlow in one direction in said first winding 'for operating' said relay toclose a locking circuit tor itself including" said second windiire'1 means for .producing a current [low in the other direction in said tirst winding to deenergize said relay, said locking' circuit bcing opened thereby, and means controlled by said relay for transmitting' digit impulses.

2. In a telephone system, a trunk line divided into sections iuductivelycoupled. means for producing a direct (uu-rent i1upulse in the outgoing section, said impulse causing two impulses in said incoming sec tion, and a relay in said incoming section responsive to saidfirst impulse to close a locking circuit for itself and responsive to said vsecond impulse to `open said locking cir cuit. y y 1 i f 3. In a telephone system. a trunk line divided into sections inductively coupled. means for producing a direct current inipulse in the outgoing section. said inundar causing a first induced impulse current; in one direction anda second induced current impulse in the other direction in the incoln ing section, an impulse repeating relay. and an impulse receiving relay responsive to said first induced current impulse to close a circuit for said in'ipulse repeating relay and responsive to said second induced impulse to open said circuit. y i

Ll. In a telephone system, a trunk line divided into sections inductively coupled.` means for momentarily.causing a` dirwft cui rent :flow in the outgoing se 'ion causing au induced impulse oi one nature in the incolun ing section at the start of said direct current and au induced impulse of a different nature at the termination oi said direct current in the incomingsection otsaid truuk line, an impulse repeating relay, and an impulse rcceiving relay responsive to said first induced impulse to close a circuit for said impulse repeating relay and responsive to said ser -ond induced impulse to open, said circuit.

f1 Ia telephone System friuli lia@ aillit() lll) ien

vided into sections inductively` coupled,

means for producing a" direct current imone direction and a second induced current impulse iu the other direction in the `in-` coming section, animpulse repeating relay, and an impulse receiving'irelay responsive to said first induced currentimpulse to close a circuit for said impulse `rel'aeating relay and responsive to said second induced im pulse to open said circuit.

6. In a vtelepluine system, a trunk line divided into sections inductively coupled,

' vmeans for prmlucing a direct current in the outgoing section ofthe trunk line, means lor mon'ientarily causing an induced inipulse oil oner nature in theincoming section at the start oit said direct current and an iiuluced impulse of adilierent natuijc 'furthe incoming section at the,termination'of said direct current inthe outgoing section of said trunk luie, animpulse repeating relay, an impulse receiving relay responsive to said iirst vin-` duced impulse to close a circuit for said iinpulse repeatmgrelayand responsive to'said second induced impulse to open saidv circuit,

and damping means in the outgoing section for causing' the tivo induced impulses inthe incoming section to he of similar nature though opposite in direction.

7. In a telephone system, a trunk line di vided into sections inductively coupled, means i"or producing a direct current im pulse in the outgoing section, said impulse ia-using a iirst induced impulse current in one direction and a second induced current .impulse in the other direction in the incoming section, an impulse repeatinfrrelay, an impulse receiving relay responsive to said lirst induced current impulse to close a cir-` cuit itor said impulse repeating relay and responsive to said second induced impulse to open said circuit, damping means in the outgoing section. lor causing the two induced impulses in the incoming section to he of similar nature, and means for disconnecting said damping means.

5%. ln a telephone system, a trunk line divided into sections inductively coupled, means for producing a direct current in the outgoing section of the trunk line, means for momentarily causing an induced impulse of one nature in the incoming section at the start oi' said direct current and an induced impulse of a different nature in the incoming section at the termination of said direct current in the outgoing section of said trunk line, an impulse repeating relay, an impulse receiving relay responsive to said first induced impulse to close a. circuit for said impulse repeating relay and responsive to said second induced impulse to open said circuit, damping means in the outgoing' sec-tion for causing the tivo induced impulses in the iincon'iingsection to be oisimilar nature though opposite in direction, and `means for disconnecting said damping means.

9.' 'In ai divided into c, sections means for producing a direct current impulse in the outgoing section, said impulse rcausing `a .'lirst induced impulse `current in telephone system,` a trunkA line `one direction and a. second induced current impulse in the other direction in the incoming section, an impulse repeating rela', an impulse receiving relay responsive to said first induced current impulse to close a circuit `for said impulse repeating relay and responsive vto said second induced impulse to open said circuit, and damping means inductively coupled to saidV outgoing section for causing the two induced impulses `inthe incoming section to ot `simi ar naturethough, opposite in direction.

l0. In a telephone system, a trunlcline divided into sections inductively coupled, meanstor momentarily causing a direct cur- `rent liowin the outgoing section causing an `induced impulse oii oneA nature in the incom ing section at the startet' said direct current and aninduced impulse of different nature .in the Cincomingfsection at the termination of said "direct current in the outgoing `section of saidtrunlz line, an impulse repeating relay, an impulse receiving relay responsive` to said first induced impulse to close a circuit for said impulse repeating relay, and

said direct current in the outgoing section` of said trunk line, an impulse repeating relay, an impulse receiving relay responsive to said first induced impulse to close a circuit for said impulse repeating relay and responsive to said second induced impulse to open said circuit, and means controlled by saidy impulse repeating relay for reducing the current flow in its circuit after said circuit is established.

l2, In a telephone system a trunk line having a circuit inductively coupled therewith, means for successively establishing and disrupting a direct current low in said circuit, means for causing the rate of rise and the rate of decay of current in said circuit to be substantially the saine, and a relay Connected to, said trunk line to respond t@ inductively coupled,

the impulses induced therein by the rise and fall of current in said circuit. y

13. In a telephone system a trunk line having a circuit induetively coupled therewith, means for successively establishing and disrupting a direct current liow in said circuit, means for causing the rate of rise and the rate of decay of current in said circuit to be substantially the same, and a relay connected to said trunk line to respond to the impulses induced therein by the rise and fall of current in said circuit, said relay being operated by one impulse and said relay having a locking winding etective when the relayfis operated to maintain the relay operated, said relay being deenergized and` released by the succeeding impulse which is .in the opposite direction to the preceding impulse.

14. Means for repeating impulses lfrom a .first circuit to a second circuit, said means including a relay which is ope ated and released by successive impulses of opposite polarity, means for sending one impulse to said relay responsive to commencement of an impulse in the rst circuit and for send- `ing an impulse of opposite polarity to said relay responsive to the cessation of the inipulse in the first circuit, and means for holding said relay in its operated position during the interval between impulses.

an ope ating winding and locking Winding ing being in a circuit which is indnctively coupled with a second circuit, means for causingr an increasing current How in thc second circuit whereby the relay is operated over the operating winding and locked over the locking windingand meanslor causing a decrease in the current flow in the second circuit whereby an opposing current flow is produced in the operating winding to rclease the relay.

16. A relay having a lirst and a second winding, means 'for producing a current tlowin one direction in said lirst winding for operating said relay, means ell'ectivc when the relay is operated :tor closing a lockingcircuit for the relay said locking circuit including the second winding, means eli'ective when the relay is operated over the second `winding `t'or reducing the current tiow through the second winding, and means for producing a current iloW in the opposite direction in the iirst winding to deenergize said relay, said locking circuit being opened thereby. c

In witness whereof, I hereunto subscribe my naine this 24th day of February, A. l). 1926. i

ARTHUR man. 

